skiagd

skiagd is a toy R wrapper for rust-skia (the rust crate skia_safe, a binding for Skia).

Despite its name, this package is intended as a graphics library, not a graphics device for R 😓

Design notes

• This is not a graphics device. skiagd does not allow R’s session to hold a reference to a Canvas object on Rust side.
• Drawing functions return a picture as a raw object every time it’s called. add_* puts those data onto canvas, actually adds some paintings to there, and then returns a raw object again.

Future plan

I’m planning to re-implement features like React Native Skia.

Maybe in the near future??

• Shapes
  • Path
    • SVG notation (path)
  • Polygons
    • Rect
    • RoundedRect (round_rect)
    • DiffRect (drrect)
    • Line
    • Points (points; not point)
  • Ellipses
    • Circle
    • Oval (oval)
    • Arc (arc)
  • Atlas
  • Vertices
  • Patch
• Images
  • PNG
• Text
  • Paragraph
  • Text
  • Glyphs
  • Text Path
  • Text Blob
• Painting Attributes (Paint)
  • PathEffects
  • MaskFilter?? (blur)
  • ImageFilters
  • Shaders
  • RuntimeShaders
    • sksl support
    • uniforms support

Possibly in the future??

• Fitting Images (needs to re-implement this)
• Group / Backdrop Filters
• Mask

Showcase

It’s still in early alpha stage. The API is subject to (maybe drastic) change.

pkgload::load_all(export_all = FALSE)
#> ℹ Loading skiagd

img_data <-
  unigd::ugd_render_inline({
    set.seed(1234)
    size <- dev_size("px")
    n_circles <- 250
    canvas("snow") |>
      add_line(
        matrix(c(runif(300, 0, size[1]), runif(300, 0, size[2])), ncol = 2),
        matrix(c(runif(300, 0, size[1]), runif(300, 0, size[2])), ncol = 2),
        props = paint(color = "#fff28166", width = 6)
      ) |>
      add_circle(
        matrix(c(runif(n_circles,  0, size[1]), runif(n_circles, 0, size[2])), ncol = 2),
        runif(n_circles, 6, 50),
        props = paint(color = "#87ceeb66", blend_mode = BlendMode$ColorBurn)
      ) |>
      add_circle(
        matrix(c(runif(n_circles, 0, size[1]), runif(n_circles, 0, size[2])), ncol = 2),
        runif(n_circles, 20, 60),
        props = paint(color = "#ff1493aa", blend_mode = BlendMode$Overlay)
      ) |>
      add_path(
        "M 128 0 L 168 80 L 256 93 L 192 155 L 207 244 L 128 202 L 49 244 L 64 155 L 0 93 L 88 80 L 128 0 Z",
        transform = c(1, 0, (size[1] / 2 - 128), 0, 1, (size[2] / 2 - 128), 0, 0, 1),
        props = paint(color = "#fff281ee")
      ) |>
      draw_img()
  }, as = "png", width = 1280, height = 720)

img_data |>
  magick::image_read() |>
  as.raster() |>
  plot()